(Fluoroorgano)fluoroboranes and -fluoroborates. 2 [1]: Synthesis and spectroscopic characterization of potassium polyfluoroalken-1-yltrifluoroborates

Article abstract of DOI:10.1002/1521-3749(200111)627:11<2499::aid-zaac2499>3.0.co;2-z

The potassium fluoroborates K[RCF=CFBF₃] (R = F, Cl (cis-/trans-mixture), trans-C₄F₉, cis-C₂F₅, cis-C₆F₁₃, trans-C₄H₉, trans-C₆H₅) wer

Full text of DOI:10.1002/1521-3749(200111)627:11<2499::aid-zaac2499>3.0.co;2-z

ꢀFluoroorgano)fluoroboranes and -fluoroborates. 2 [1]
Synthesis and Spectroscopic Characterization
of Potassium Polyfluoroalken-1-yltrifluoroborates
H.-J. Frohn a,* and V. V. Bardin b
a Duisburg, Fachgebiet Anorganische Chemie, Gerhard-Mercator-UniversitaÈt
b Novosibirsk/Russia, N. N. Vorozhtsov Institute of Organic Chemistry
Received March 2nd, 2001.
Abstract. The potassium fluoroborates K[RCF=CFBF3]
2R = F, Cl 2cis-/trans-mixture), trans-C4F9, cis-C2F5, cis-
C6F13, trans-C4H9, trans-C6H5) were prepared by fluorida-
tion 2methoxide-fluoride substitution with K[HF2]) of
RCF=CFB2OMe)2 and Li[RCF=CFB2OMe)3] which were
obtained
from
RCF=CFLi
and
B2OMe)3.
The
K[RCF=CFBF3] salts were characterized by their 1H, 11B,
19F NMR and IR spectra.
Keywords: Borates; Polyfluoroalken-1-yl; NMR spectroscopy
ꢀFluororgano)fluorborane und -fluoroborate. 2 [1]
Synthese und spektroskopische Charakterisierung
von Kalium Polyfluoralken-1-yltrifluoroboraten
InhaltsuÈbersicht. Die Kalium Fluoroborate K[RCF=CFBF3]
2R = F, Cl 2cis-/trans-Gemisch), trans-C4F9, cis-C2F5, cis-
C6F13, trans-C4H9, trans-C6H5) werden durch Fluoridierung
2Methoxid-Fluorid-Substitution mit K[HF2]) von RCF=CFB-
2OMe)2 und Li[RCF=CFB2OMe)3] dargestellt. Letztere re-
sultieren aus der Umsetzung von RCF=CFLi mit B2OMe)3.
Die K[RCF=CFBF3] Salze werden durch ihre 1H, 11B, 19F
NMR und IR Spektren charakterisiert.
Introduction
borates [3]. The reactivity of the corresponding bor-
anes in fluoro-alkenyl substitution reactions will be
discussed in forthcoming papers.
Recently we have reported a simple and convenient
synthesis of potassium salts of polyfluoroaryltrifluoro-
borates K[C6H5±nFnBF3] 2n = 1±5) and of perfluoro-
alkyltrifluoroborates K[CnF2n+1BF3] 2n = 3, 6) by the
fluoridation of the corresponding dialkoxyboranes
OrgFB2OMe)2 and trialkoxyborates M[OrgFB2OMe)3]
using K[HF2] [1, 2]. Those intermediate boranes and
borates were obtained by the reaction of fluoro-con-
taining organomagnesium or lithium reagents with
B2OAlk)3 and used in the further synthetic route
without isolation.
Fluorinated alkenyltrifluoroborates are a still un-
known class of organoelement compounds despite
their high synthetic potential. In the course of sys-
tematic investigations of fluoro-containing organo-
boron compounds as precursors for the synthesis of
organoxenonium salts [OrgFXe]+Y±, we elaborated a
general route to potassium fluoroalken-1-yltrifluoro-
Results and Discussion
The preparation of potassium fluoroalken-1-yltrifluoro-
borates was performed analogously to the general
scheme for the synthesis of fluoroaryl- and fluoroal-
kyltrifluoroborates.
BꢀOMe†
3
RCF=CFLi
! RCF=CFB2OMe)2 +
K‰HF2Š
Li[RCF=CFB2OMe)3]
! K[RCF=CFBFn2OMe)3±n
]
aq: MeOH
40% HF; aq: MeOH
! K[RCF=CFBF3]
R = F 21), cis-, trans-Cl 22), cis-C2F5 23), cis-C6F13 24), trans-
C4F9 25), trans-C4H9 26), trans-C6H5 27). The position of sub-
stituent R is related to the BF3 group.
We were very interested in the pure cis- and/or trans-
2-R-1,2-difluoroethen-1-yltrifluoroborate salts. Taking
into account that our favoured route consists of sev-
eral steps it was therefore useful to generate the orga-
nolithium nucleophiles as substrates by the most sim-
ple and reliable procedure. Hence we had to apply
different routes to the desired alkenyllithium sub-
strates. One of them is based on the metallation of
* Prof. Dr. H.-J. Frohn,
Fachgebiet Anorganische Chemie der UniversitaÈt,
Lotharstr. 1,
D-47048 Duisburg,
Fax: 2+49)2 03-3 79 22 31
e-mail: frohn@uni-duisburg.de
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001 0044±2313/01/6272499±2505 $ 17.50+.50/0 2499

H.-J. Frohn, V. V. Bardin
polyfluorinated alkenes RCF=CFH with BuLi. The
trans-RCF=CFH substrates 2R = C4H9, C6H5) were
prepared using the method of Normant et al [4, 5]
from the corresponding trifluorovinyltrimethylsilane.
fluoroaryl-trialkoxyborane system [1], no diorganyl-
2methoxy)boranes as well as diorganyldimethoxybo-
rates were found in the polyfluoroalkenyl-B2OMe)3
system.
Furthermore,
the
fluoridation
of
RCF=CFB2OMe)2 and Li [RCF=CFB2OMe)3] with
K[HF2] in aqueous MeOH proceeds incompletely and
gives a mixture of K[RCF=CFBFn2OMe)3±n] while
the previously investigated fluorodealkoxylation of
both ArB2OR')2 and [ArB2OR')3]± [1, 10, 11] or of
the acids ArCH=CHB2OH)2 [12, 11] ends with the
corresponding potassium organyltrifluoroborates. We
assume that the replacement of the substituent Org in
the borane OrgB2OR')2 2Org = Ar, ArCH=CH) by
higher electron-withdrawing Org-groups increases the
Lewis acidity of the borane and hinders the elimina-
tion of the anion [OR']± from the corresponding bo-
rate [OrgBFn2OR')3±n]±. However, the protonation of
the oxygen atom by acidification with HFaq facilitates
the leaving of the oxygen-containing group from the
boron atom as R'OH 2or its protonated form) and al-
lows to obtain the desired salts K[RCF=CFBF3] in
good yields. The influence of acidity on the fluoro-
dealkoxylation of alkoxyboranes is well demonstrated
by a model reaction of K[HF2] with B2OMe)3 in aqu-
eous MeOH. Even in excess of K[HF2] the salt
K[BF32OMe)] is the predominant product and K[BF4]
only the minor one.
CF2=CFSiMe3 + RLi ® trans-RCF=CFSiMe3
KF‡H2O
BuLi
! trans-RCF=CFH ! trans-RCF=CFLi
R = C4H9, C6H5
However, this pathway is not available for the stereo-
selective preparation of trans-CnF2n+1CF=CFH be-
cause perfluoroalkylllithium reagents have too low nu-
cleophilicity and insufficient thermal stability. The
required trans-1 H-perfluoro-1-hexene was obtained
by Burton's method [6] via the stereospecific nucleo-
philic phosphodefluoridation of the easily available
perfluoro-1-hexene.
1: PBu3
C4F9CF=CF2
BuLi
! trans-C4F9CF=CFH
2: H2O
! trans-C4F9CF=CFLi
The pure cis-1,2-difluoroalkenes RCF=CFH are less
convenient available than the trans-isomers. With
R = CF3 or C2F5, they can be obtained by the isomeri-
sation of trans-CF3CF=CFH or CF2=CFCF2CF2H
with SbF5 [6, 7]. This procedure can not be applied to
hydroperfluoroalkenes with longer chains because
they give a mixture of internal isomers in addition to
the desired products [8]. We assumed that the for-
mation of CF2=CFLi from CF3CFH2 via CF3CFHLi
developed by different English groups [9] may have a
general character, and that the elimination of LiF
from the related intermediate RCF2CFHLi may lead
to cis-olefins RCF=CFH rather than to trans-olefins.
Indeed, the treatment of 1 H,1 H-perfluorooctane with
two equivalents of BuLi resulted in the formation of
cis-perfluorooctenyllithium with a negligible impurity
of the trans-isomer 2< 5%).
> 3 K[HF2] + B2OMe)3
MeOH; H2O
! K[BF4] + K[BF32OMe)] + K[BFn2OMe)4±n
]
4
:
96 minor
n = 2, 1
Potassium polyfluoroalken-1-yltrifluoroborates 1±7
are air- and moisture-stable colourless solids which
are soluble in polar organic solvents 2acetone, MeCN,
MeOH, DMF, diglyme). Salts 1±3 are soluble in water
while the other ones only show a poor solubility.
The 11B NMR spectra of salts K[RCF=CFBF3] dis-
play the weak influence of the substituent R on the
shielding of the boron atom. All 11B resonances of
salts 1±7 are located at 0.3 ± 0.5 ppm 2Table 1). Similar
values were found for the salts K[C6H5±nFnBF3]
2n = 1±5) [d2B) 2.76 ± 0.95] [1] and for the perfluoro-
alkyltrifluoroborates K[CnF2n+1BF3] [d2B) ±1.7 2n = 1)
[13], ±0.64 2n = 3), ±0.53 2n = 6)] [2]. The recently re-
ported 11B NMR data of Cs [CF2=CFB2CF3)2F]
showed a more shielded boron atom 2Table 1) caused
by the replacement of the fluorine atoms at boron by
less electronegative trifluoromethyl groups [14]. In the
case of K[trans-RCH=CHBF3] with R = Ph, C4H9 and
H the resonances are found at 3.8 2R = Ph), 3.6
2 BuLi
C6F13CF2CFH2
! cis-C6F13CF=CFLi
A mixture of cis-, trans-ClCF=CFLi was prepared
from 1,2-dichlorodifluoroethene and t-BuLi in pen-
tane-ether at ±90 °C.
The reactions of all above mentioned organolithium
reagents RCF=CFLi with B2OMe)3 led to the forma-
tion of organyldimethoxyboranes and lithium organyl-
trimethoxyborates. Those organoboron derivatives were
observed in the reaction mixture by 19F-NMR spectro-
scopy but for the current purpose they were used with-
out isolation. However, the preparation and characteri-
zation of the individual compounds RCF=CFB2OR')2
and M[RCF=CFB2OR')3] 2R' = alkyl, H; M = counter-
cation) will be described elsewhere.
1
2R = C4H9) and 3.4 2R = H) ppm and the J2BF) coup-
ling constants are 46, 52 and 56 Hz, respectively [11],
which are significantly larger than in the 1,2-difluor-
oalken-1-yltrifluoroborate series.
Although the preparation of K[RCF=CFBF3] looks
at first sight like the earlier described synthesis of
K[C6H5±nFnBF3] [1], nevertheless there are two dis-
tinctions between them. In contrast to the poly-
The 19F resonances of the BF3 groups of the salts
K[RCF=CFBF3] are located at ±142 to ±144 ppm 2Ta-
2500
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505

2Fluoroorgano)fluoroboranes and -fluoroborates. 2
ble 2). It is noteworthy that the boron-bonded fluorine
atoms in the anions [cis-RCF=CFBF3] 2R = Cl, C4F9,
C6F13) are slightly deshielded with respect to the cor-
responding trans-isomers. Deshielding also takes place
after replacement of the electron-withdrawing substi-
tuents R = F, C4F9, C6F13 by chlorine or C4H9, C6H5
groups 2in acetonitrile solution).
An interesting solvent-dependence was found for
d2F-1). Going from the polar aprotic solvents 2ace-
tone, acetonitrile) to the protic ones like water and
methanol, the resonance of the F-1 fluorine atom
shifts 3±5 ppm to higher frequency 2R = F, cis-, trans-
Cl). Simultaneously the resonance of the F-2 trans
atom 2R = F, cis-Cl) undergoes a smaller but still re-
markable opposite shift. This effect cannot be as-
signed to differences in the dielectric constants of
MeOH and MeCN because they are similar. Probably,
the observed solvent-dependence arises from the for-
mation of hydrogen bonds between the solvent mole-
cules and the fluorine atoms bonded to boron. Unfor-
tunately, the solubility of the other salts 3±7 is not
high enough to examine the validity of our assumption
Table 1 The 11B NMR spectra of K[RCF=CFBF3]a),b)
R
d2B)
1J2B,F)
2J2B,F-1)
Fc),d)
Cl
cis-C2F5
cis-C6F13
trans-C4F9
trans-C4H9
trans-C6H5
Ff)
0.66
0.2±0.4e)
±0.07
±0.17
±0.17
0.68
42
25
c)
37
36
39
43
42
56.9
23
23
26
31
28
23
0.65
±6.4
a)
The position of substituent R is given with respect to the boron atom.
b)
c)
d)
e)
f)
In MeCN.
3J2B,F-2trans) 7 Hz.
In acetone.
Resonances are overlapping.
Salt Cs [CF2=CFBF2CF3)2] [14].
Table 2 The 19F NMR spectra of K[RCF=CFBF3]a)
R
Solvent
d2F)
J, Hz
F-1
F-2cis
F-2trans
BF3
1,B
1,2trans
1,2cis
2cis,BF
2cis,2trans
BF
Fb)
acetone
MeCN
H2O
MeOH
acetone
MeCN
MeCN
acetone
MeCN
D2O
acetone
MeCN
MeCN
acetone
MeCN
acetone
MeCN
acetone
MeCN
D2O
acetone
MeCN
MeCN
acetone
MeCN
±194.46
±195.65
±199.87
±198.49
Cl
±124.41
±124.00
±123.36
±122.94
±92.27
±92.71
±124.3
±126.20
±126.51
±126.09
±177.33
±177.16
±177.08
±162.81
±161.83
±157.11
±156.82
±
±102.24
±101.16
±98.71
±99.02
±82.17
±82.45
±99.5
±
±143.36
±143.35
±143.46
±143.79
±141.46
±141.32
±229.9
24
25
25
25
25
25
24
±
±
25.5
±
±
±
±
±
110
110
110
108
±
8
7
9
9
10
9
17.8
9
8
92
92
87
90
52
54
87.7
±
±
±
±
±
±
±
±
±
±
±
±
±
41
41
40
Fc)
F
Fd)
F
±
±
23
30
26
26
F
Cl
±195.7
±
40
56.9
Fe)
110.9
127
129
128
128
130
125
117
118
119
118
±
±
±
±
±
±
±
±
trans-Cl
trans-Cl
trans-Cl
trans-C4F9
trans-C4F9
trans-C6F13
trans-C6H5
trans-C6H5
trans-C4H9
trans-C4H9
cis-Cl
±157.59
±157.14
±162.37
±151.74
±153.06
±153.34
±158.53
±160.32
±170.57
±170.74
±147.26
±146.93
±151.53
±131.73
±131.73
±130.82
±128.98
±131.19
±143.10
±142.89
±142.84
±143.87
±144.03
±144.17
±142.16
±142.13
±141.93
±142.00
±143.10
±142.58
±142.25
±142.30
±142.47
±142.50
±142.45
±142.61
±
40
40
42
39
±
±
±
±
9
f),g)
h),g)
26
i),g)
±
±
±
±
j)
±
28
28
9
10
9
±
±
±
42
43
k)
l)
31
24
25
24
23
23
25
±
9
±102.50
±103.11
±100.94
±156.81
±157.47
±156.37
±157.15p)
±156.23
±
±
±
±
±
±
±
±
cis-Cl
cis-Cl
±
39
40
37
37
37
±
±
±
±
±
±
m)
cis-C2F5
cis-C2F5
cis-C4F9
cis-C6F13
cis-C6F13
±
±
±
±
n)
o)
q)
r)
23
±
34
a)
The fluorine atoms F-2 are marked by cis or trans relative to the position of the BF3 group.
3J21,BF) 5.4, 4J22trans,BF) 9, 3J22trans,B) 7.4.
b)
c)
d)
e)
f)
4J22trans,BF) 8.
4J22trans,BF) 9.
Salt Cs [CF2=CFBF2CF3)2] [14].
d2F): ±80.17 23 F-6), ±115.28 22 F-3), ±123.63, ±125.23 22 CF2).
Tentative assignment of the F-1 and F-2 resonances.
d2F): ±80.41 23 F-6), ±115.95 22 F-3), ±124.12, ±125.60 22 CF2); 4J24,6) 10.
d2F): ±115.91 22 F-3); the other signals overlap with resonances of the trans-isomer.
d2H): 7.88.
g)
h)
i)
j)
k)
l)
d2H): 2.21 22 H-3), 1.39 24 H-4,5), 0.88 23 H-6); 4J2H-3,H-5) 6, 4J2F-1,H-3) 6, 3J2F-2,H-3) 23.
d2H): 2.29 22 H-3), 1.41 24 H-4,5), 0.90 23 H-6); 4J2H-3,H-5) 7, 4J2F-1,H-3) 6, 3J2F-2,H-3) 23.
d2F): ±83.24 23 F-4), ±117.62 22 F-3).
m)
n)
o)
p)
q)
r)
d2F): ±83.52 23 F-4), ±117.79 22 F-3); 3J22,3) 12, 4J22,4) 8, 5J23,BF) 12.
d2F): ±114.58 22 F-3); the other signals overlap with resonances of the trans-isomer.
4J2F-2,BF) 10.
d2F): ±79.96 23 F-8), ±113.65 22 F-3), ±121.42, ±124.98 24 CF2).
d2F): ±80.37 23 F-8), ±114.54 22 F-3), ±121.42, ±121.97, ±125.40 24 CF2).
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505
2501

H.-J. Frohn, V. V. Bardin
1H-NMR 2CDCl3): 7.41; J, Hz: 2H,F-1) 70.4, 2H,F-2) 4.6.
as a general property in the class of alkenyltrifluoro-
borates.
19F-NMR 2CDCl3): ±82.03 2F-6), ±119.75 2F-3), ±125.80 2F-4), ±127.42
2F-5), ±164.32 2F-1), ±176.82 2F-2); J, Hz: 21,H) 71, 21,2) 135, 21,3) 23,
21,4) 5, 23,5) 10, 24,6) 9.
IR 2neat) mª
2cm±1): 2984 m, 2876 m, 1774 w, 1718 m, 1688 w, 1448 w,
1383 m, 1352 s, 1296 m, 1241 vs, 1207 vs, 1190 vs, 1140 vs, 1022 m, 927 w,
877 s, 837 s, 792 m, 745 s, 714 m, 678 w, 628 w, 594 w, 519 w.
Experimental
NMR spectra were measured on Bruker spectrometers
WP 80 SY 21H at 80.13 MHz and 19F at 75.39 MHz) and
Avance DRX 500 21H at 500.13 MHz, 11B at 160.46 MHz
and 19F at 470.59 MHz). Chemical shifts were reported with
respect to TMS 21H), BF3 ´ OEt2 211B) and CCl3F 219F). IR
spectra were recorded on a Bruker Vector 22 instrument as
KBr pellets. Elemental analysis was performed in the
N. N. Vorozhtsov Institute of Organic Chemistry, Novosi-
birsk.
1 H,1 H-Perfluorooctanol-1 2Clariant), 1 H,1 H,5 H-octa-
fluoropentanol-1 2Acros), 1.6 M and 2.5 M BuLi in hexanes,
1.7 M t-BuLi in pentane, 1.8 M PhLi in cyclohexane-ether
2Aldrich), KF 2spray-dried) 2Morita), K[HF2] 2Fluka), tribu-
tylphosphane 2Fluka), 40% HF 2Riedel-deHaen), perfluoro-
butanesulfonyl fluoride 2Merck), 1,2-dichlorodifluoroethene
2Bristol Organics) 2contains 9% of 1,1-dichlorodifluoro-
ethene) were used as supplied.
B2OCH3)3 2Aldrich) was distilled over Na before use.
Antimony pentafluoride 2N. N. Vorozhtsov Institute of Or-
ganic Chemistry, Novosibirsk) was distilled in a dry argon
atmosphere. Diglyme 2Merck), triglyme 2Merck), THF
2Baker), dichloromethane, ether, triethylamine, chlorotri-
methylsilane were purified and dried using standard proce-
dures. Hydrogen fluoride was dried by electrolysis 2stainless
steel cell, Ni-electrodes).
Fluoroalkenes trans-RCF=CFH 2R = C4H9 [4], C6H5 [5])
were prepared from trimethylsilyldifluoroalkenes trans-
RCF=CFSiMe3 and KF in aqueous DMSO using the litera-
ture procedures and distilled before use.
1 H,1 H-Perfluorooctyl nonaflate. A solution of 1 H,1 H-per-
fluorooctanol-1 210.0 g, 25 mmol) and triethylamine 22.6 g,
26 mmol) in dichloromethane was cooled to 0 °C and per-
fluorobutanesulfonyl fluoride 210.0 g, 33 mmol) was added
drop by drop under stirring. The reaction mixture was stirred
at 0 °C for 30 min and at room temperature for 1 h. The vo-
latile products were removed 2evaporator) and the residual
oil was dissolved in ether 280 ml). The etherial solution was
washed with water and dried with MgSO4. After removal of
the solvent under reduced pressure 1 H,1 H-perfluorooctyl
nonaflate 216.2 g, 95%) was obtained.
C12H2F24O3S 2682,17): calculated C 21.13, H 0.30, F 66.84,
S 4.70; found C 21.3, H 0.30, F 66.9, S 5.20%.
1H-NMR 2CF2ClCFCl2): 4.86 ppm. 19F-NMR 2CF2ClCFCl2): ±80.88
22 CF3), ±109.58 2CF2), ±119.56 2CF2), ±120.71, ±121.41, ±122.38 25 CF2),
±125.69 22 CF2) ppm.
IR mª
2cm±1): 3057 w, 3002 w, 2970 w, 2924 w, 2851 w, 1630 w, 1419 s,
1358 m, 1328 m, 1299 m, 1264 sh, 1237 vs, 1204 vs, 1146 vs, 1109 m, 1043 s,
1010 s, 958 m, 880 w, 839 w, 803 m, 773 m, 736 m, 701 m, 664 m, 647 m,
620 w, 596 m, 574 w, 533 m, 505 w, 482 m, 455 w.
1 H,1 H-Perfluorooctane. 1 H,1 H-Perfluorooctyl nonaflate
217.8 g, 27 mmol) and KF 27.6 g, 131 mmol) were stirred in
triglyme 2150 ml) at 170±200 °C. During 5 h the volatile pro-
ducts distilled off. The distillate was washed with water
23 ´ 5 ml) and dried with MgSO4. The yield of 1 H,1 H-per-
fluorooctane was 8.2 g 275%). 1H-NMR 2neat): 4.69 ppm.
19F-NMR 2neat): ±82.1 2CF3), ±123.2, ±124.4, ±126.9 26 CF2),
±244.3 2CH2F) ppm; J, Hz: 2H,F-1) 46, 2H,F-2) 11.
All manipulations with moisture-sensitive compounds
were performed under dry argon atmosphere.
trans-1,2-Difluorohexen-1-yltrimethylsilane. CF3CH2F 212.3 g,
121 mmol) was condensed into cold ether 2100 ml, ±55 °C).
2.5 M BuLi 2100 ml, 250 mmol) was added drop by drop to
the ±75 °C solution within 15 min. The solution was stirred at
±60 °C for an additional hour. Chlorotrimethylsilane 214.2 g,
129 mmol) was added to the solution within 5 min. After
30 min of stirring at ±60 °C a solution of trifluorovinyltri-
methylsilane 219F-NMR) was obtained.
Preparation of starting compounds
Perfluoro-1-hexene. C6F13COONa 287 g, 225 mmol) was
heated at 200±300 °C under reduced pressure 240±60 hPa).
The gaseous products were collected in two traps cooled at
±70 to ±80 °C and later warmed to room temperature,
washed with water and dried with MgSO4 and P4O10. After
distillation perfluoro-1-hexene was obtained in 89% yield
260 g) 2b. p. 55±56 °C, lit. 57 °C [15], 50±51 °C [16]) 2The pro-
duct contained ca. 6% of trans-C3F7CF=CFCF3 219F-NMR)).
A further portion of 2.5 M BuLi 250 ml, 125 mmol) was
added at £ ±50 °C and the resulting solution was warmed to
room temperature. After washing with 10% HCl 2300 ml)
the organic phase was dried with MgSO4 before the solvent
was removed. Trans-1,2-difluorohexen-1-yltrimethylsilane
216.5 g, 71%) was isolated by vacuum-distillation, b. p. 60±
62 °C 233 hPa) 2lit. 50±52 °C 215 hPa) [4]).
trans-1 H-Perfluoro-1-hexene. Tributylphosphane 219.9 g,
98 mmol) was added drop by drop into a stirred emulsion of
perfluoro-1-hexene 229.6 g, 98 mmol) in diglyme 2150 ml) at
±50 °C within 30 min. The reaction mixture was slowly
warmed to room temperature and showed the formation of
trans-C4F9CF=CFPFBu3 [d2F): ±15.8 2d, PF, 1J2FP) 611),
±81.8 2CF3), ±116.7 22 F-3), ±125.7 and ±127.4 22 CF2), ±138.0
and ±166.7 2F-1 and F-2) ppm]. After addition of water
22 ml) the volatile products were distilled from the stirred
solution at 120 to 130 °C 2bath) during 3 h. The distillate was
washed with water, dried with MgSO4 and P4O10 and re-dis-
tilled to yield 16.7 g 260%) of trans-1 H-perfluoro-1-hexene,
b. p. 55±58 °C.
C9H18F2Si 2192,32): calculated C 56.21, H 9.43, F 19.76;
found C 56.5, H 9.43, F 19.9%.
1H-NMR 2CDCl3): 2.36 22 H-3), 1.46 24 H-4,5), 0.92 23 H-6), 0.20
2SiCH3) ppm; J2H-3,H-5) 7. 19F-NMR 2CDCl3): ±146.64 2F-2), ±175.00
2F-1) ppm; J, Hz: 2F-1,F-2) 126, 2F-1,H-3) 6, 2F-2,H-3) 23.
trans-1,2-Difluoro-2-phenylethen-1-yltrimethylsilane. A solu-
tion of CF2=CFSiMe3 prepared from CF3CH2F 212.6 g,
124 mmol), 2.5 M BuLi 2100 ml, 250 mmol) and ClSiMe3
214.5 g, 132 mmol) in ether 2250 ml) 2see above) was reacted
with 1.8 M PhLi in cyclohexane-ether 269 ml, 124 mmol) as
described before. After removal of the solvent crude trans-
1,2-difluoro-3-phenylethen-1-yltrimethylsilane 223 g) which
C6HF11 2282,06): calculated C 25.55, H 0.36, F 74.09;
found C 26.0, H 0.42, F 73.8%.
2502
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505

2Fluoroorgano)fluoroboranes and -fluoroborates. 2
contained 16% of trans-BuCF=CFSiMe3 was obtained and
used for the preparation of trans-C6H5CF=CFH without pu-
rification.
250 ml) and MeOH 210 ml). The reaction mixture was stirred
overnight before it was saturated with KF and extracted with
MeCN 23 ´ 40 ml). The combined extracts were dried with
Na2SO4 and evaporated to dryness. After washing with dry
ether potassium trifluorovinyltrifluoroborate was obtained
29.3 g, 59% based on CF3CFH2).
5 H-Octafluoropentanoic acid. A three-necked 0.5 l flask was
charged in sequence with water 2110 ml), H2SO4 252 ml) and
Na2Cr2O7 235 g, 0.13 mol). Then 1 H,1 H,5 H-octafluoropen-
tanol-1 230.3 g, 0.13 mol) was added drop by drop at 95±
98 °C under stirring within 15 min. The reaction mixture was
refluxed for 4 h, cooled to 25 °C and extracted with ether
23 ´ 150 ml). The extracts were dried with MgSO4 before the
solvent was removed 2evaporator). Conc. H2SO4 2100 ml)
was added to the residual dark oil and the resulting solution
was heated to 180±190 °C 2bath) under stirring. Simulta-
neously 5 H-octafluoropentanoic acid 228 g, 87%), b. p. 155±
158 °C distilled off.
C2BF6K 2187,92): calculated C 12.78, F 60.66, found
C 13.2, F 60.1%.
IR mª
2cm±1): 1761 vs, 1626 w, 1441 w, 1316 vs, 1293 s, 1233 vs, 1090 s, 1024 vs,
972 vs, 939 vs, 915 vs, 615 s.
Potassium trans-perfluorohexen-1-yldifluoro(methoxy)borate.
A solution of trans-1 H-perfluoro-1-hexene 23.1 g, 11 mmol)
in ether 230 ml) was cooled to ±80 °C and 1.6 M BuLi in
hexane 26 ml, 9.6 mmol) was added drop by drop within
15 min. The reaction mixture was stirred for 1 h at ±60 to
±65 °C and then transferred into the pre-cooled 2±90 °C) and
stirred solution of B2OCH3)3 21.8 g, 17 mmol) in ether
220 ml). The resulting suspension was stirred for an addi-
tional hour at ±70 to ±55 °C before it was warmed to room
temperature within 1 h. The obtained solution was evapo-
rated under reduced pressure. The residue was dissolved in
MeOH 210 ml) and poured into a solution of K[HF2] 27 g,
90 mmol) in water 250 ml). After stirring overnight the solu-
tion was saturated with KF and extracted with acetone
22 ´ 20 ml). The combined extracts were dried with MgSO4.
After evaporation of the solvent the yellow product was
washed with dichloromethane 210 ml) and dried in vacuum
to yield solid potassium trans-perfluorohexen-1-yldifluoro-
2methoxy)borate 21.7 g, 45%).
cis-1 H-Heptafluoro-1-butene. Sodium 5 H-octafluoropenta-
noate 250 g) was prepared by neutralization of 5 H-octafluoro-
pentanoic acid with aqueous NaOH, evaporation of water
and drying in vacuum at 150 °C for 4 h. The salt was pyro-
lysed at 250±280 °C for 1.5 h. Volatile 4 H-heptafluoro-1-bu-
tene 229 g) was collected in a trap at ±50 °C. For isomeriza-
tion into cis-1 H-heptafluoro-1-butene [7] it was condensed
on frozen SbF5 at ±40 °C 24 g) placed in a flask equipped
with magnetic bar, reflux condenser 2±78 °C) and inlet tube
2Warning! The contact of 4 H-heptafluoro-1-butene with
antimony pentafluoride causes an intensive heat evolution).
At the end of the isomerization the stirred mixture was care-
fully warmed to 20±25 °C. Cis-1 H-heptafluoro-1-butene
[23 g, 68% based on H2CF2)4COONa] distilled off and was
collected at ±50 °C.
C7H3BF13KO 2399,99): calculated C 21.02, H 0.76,
F 61.75; found C 21.9, H 0.99, F 61.3%.
19F-NMR 2ether): ±84.42 23 F-4), ±122.88 22 F-3), ±151.23 2F-1), ±157.16
2F-2) ppm 2lit. [7] 19F-NMR 2neat liquid): ±85.6, ±124.1, ±155.2,
±157.3 ppm, respectively).
1H-NMR 2acetone-d6): 2.96 ppm. 19F-NMR 2acetone-d6): ±80.27 2CF3),
±115.30 22 F-3), ±123.70 22 F-4), ±125.36 22 F-5), ±151.55 and ±177.54 2F-1
and F-2), ±144.00 2BF2) ppm; J, Hz: 21,2) 130, 2F,B) 36.
Potassium trans-perfluorohexen-1-yltrifluoroborate (5). A so-
lution of trans-1 H-perfluorohexene 215.2 g, 54 mmol) in
ether 2140 ml) was cooled to ±80 °C and 1.6 M BuLi in hex-
ane 235 ml, 56 mmol) was added drop by drop within 20 min.
The reaction mixture was stirred for 1 h at ±75 to ±80 °C be-
fore it was transferred into the pre-cooled 2±90 °C) and stir-
red solution of B2OCH3)3 211.3 g, 108 mmol) in ether
250 ml). Following the solution was stirred for 1 h at ±70 to
±75 °C and finally warmed to room temperature within 2 h.
The solution was concentrated to ca. 60 ml volume under re-
duced pressure and poured into a solution of K[HF2] 235 g,
449 mmol) in water 275 ml) and 40% HF 240 ml). After stir-
ring overnight the reaction mixture was saturated with KF
and extracted with ether 25 ´ 50 ml). The combined extracts
were dried with K2CO3. The solvent was evaporated and po-
tassium trans-perfluorohexen-1-yltrifluoroborate was dried
in vacuum 215.1 g, 72%).
Preparation of potassium fluoroalken-
1-yltrifluoroborates
Potassium trifluorovinyltrifluoroborate (1). 1 H,1 H-Tetra-
fluoroethane 28.6 g, 84 mmol) was condensed into THF
2100 ml) at ±75 °C and 2.5 M BuLi in hexane 263 ml,
157 mmol) was added drop by drop within 1 h. The reaction
mixture was stirred for 40 min at ±75 °C and then transferred
into the pre-cooled 2±90 °C) and stirred solution of
B2OCH3)3 216.4 g, 157 mmol) in THF 240 ml). The resulting
suspension was additionally stirred for 30 min at ±80 °C
before it was warmed to room temperature within 4.5 h. The
mother liquor was decanted. The solid residue was dissolved
in THF-MeOH. After filtration and evaporation of the sol-
vent crude lithium trifluorovinyltrimethoxyborate was ob-
tained 2white powder, 13.3 g) [d2F) 2THF): ±100.6 2dd,
F-2trans), ±123.4 2dd, F-2cis), ±192.9 2br. d, F-1) ppm). It was
suspended in 1,1,2,2-tetrachloroethane 250 ml) and ClSiMe3
215 ml) was added. After stirring at room temperature for
1 h its 19F NMR spectrum showed the formation of borane
CF2=CFB2OCH3)2 [d2F) 2THF-CH2Cl2): ±86.27 2dd, F-
2trans), ±106.92 2dd, F-2cis), ±199.30 2br. d, F-1) ppm; J2FF),
Hz: 21,2cis) 112.1, 21,2trans) 24.8, 22cis,2trans) 44.5.]. Heating
of the reaction mixture to 135±140 °C 2bath) resulted in the
simultaneous distillation of the volatile products 2b. p. 40±
72 °C). The products were distilled into a receiver which con-
tained a stirred solution of K[HF2] 220 g, 256 mmol) in water
C6BF14K 2387,95): calculated C 18.58, F 68.56; found
C 18.6, F 69.2%.
IR mª
2cm±1): 1363 m, 1332 m, 1264 s, 1240 vs, 1210 vs, 1137 vs, 1081 w,
1063 m, 1045 m, 1010 vs, 981 s, 878 m, 863 s, 770 m, 752 s, 734 vs, 702 w,
656 w, 624 m, 598 s, 569 w, 534 m, 472 m, 409 w.
Potassium trans-1,2-difluorohexen-1-yltrifluoroborate (6). A
solution of trans-1,2-difluoro-1-hexene 210.0 g, 83 mmol) in
THF 2100 ml) was cooled to ±60 °C and 2.5 M BuLi in hex-
ane 233 ml, 83 mmol) was added drop by drop within 20 min.
The reaction mixture was stirred for 0.5 h at ±60 °C and then
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505
2503

H.-J. Frohn, V. V. Bardin
transferred into the pre-cooled 2±65 °C) and stirred solution
of B2OCH3)3 215 g, 144 mmol) in THF 270 ml). After 15 min
at ±60 °C it was warmed to room temperature within 1.5 h.
The 19F-NMR spectra of the resulting suspension showed
the presence of trans-C4H9CF=CFB2OMe)2 [d2F): ±145.14
2F-2), ±173.27 2F-1) ppm; J, Hz: 2F-1,F-2) 127, 2F-2,H-3) 23]
and Li [trans-C4H9CF=CFB2OMe)3] [d2F): ±159.53 2F-2),
±170.60 2F-1) ppm; J, Hz: 2F-1,F-2) 115, 2F-2,H-3) 24]. The
suspension was concentrated under reduced pressure and
poured into a solution of K[HF2] 250 g, 641 mmol) in water
2100 ml), MeOH 220 ml) and 40% HF 250 ml). After stirring
for 6 h the reaction mixture was saturated with KF and ex-
tracted with MeCN 23 ´ 100 ml). The combined extracts were
dried with K2CO3 and evaporated in vacuum to yield potas-
sium trans-1,2-difluorohexen-1-yltrifluoroborate 29.5 g, 51%).
C6H9BF5K 2226,04): calculated C 31.88, H 4.01, F 42.02;
found C 31.5, H 4.25, F 41.9%.
with benzene 23 ´ 5 ml) and with CFCl3 25 ´ 10 ml) and dried
in vacuum to yield potassium cis-perfluoroocten-1-yltrifluoro-
borate 24.8 g, 49%).
C8BF18K 2487,97): calculated C 19.69, F 70.08; found
C 19.6, F 69.9%.
IR mª
2cm±1): 1686 s, 1627 w, 1368 m, 1330 w, 1307 m, 1293 w, 1239 s, 1204 vs,
1146 vs, 1127 m, 1071 m, 1029 s, 1000 m, 922 s, 863 w, 846 s, 805 w, 774 m,
763 s, 745 m, 714 s, 670 s, 637 m, 624 w, 610 w, 585 w, 565 w, 533 m, 483 w,
417 w.
Potassium cis-heptafluorobuten-1-yltrifluoroborate (3). A so-
lution of cis-1 H-heptafluoro-1-butene 213.9 g, 76 mmol) in
ether 2300 ml) was cooled to ±85 °C and 2.5 M BuLi in hex-
ane 232 ml, 80 mmol) was added drop by drop within 15 min
at £ ±85 °C. After stirring for 40 min, a solution of B2OCH3)3
28.1 g, 78 mmol) in ether 28 ml) was added within 10 min via
a septum using a syringe. The reaction mixture was addition-
ally stirred for 40 min at ±85 °C and then warmed to room
temperature within 1.5 h. The obtained suspension was con-
centrated to ca. 70 ml volume under reduced pressure and
formed a high viscous phase. The 19F-NMR spectrum
showed the presence of cis-1 H-heptafluoro-1-butene and
presumably, Li[cis-C2F5CF=CFB2OMe)3] [resonances at
±83.63 23 F), ±119.98 22 F), ±134.62 21 F), ±153.57 21 F) ppm]
in the 1 : 4 ratio. The viscous phase was poured into a solu-
tion of K[HF2] 247 g, 602 mmol) in water 2150 ml) and
MeOH 230 ml). The resulting two-phase system was stirred
for 1 h. The organic phase was separated, the aqueous one
was acidified with a few drops of 40% HF and extracted
with ether 23 ´ 100 ml). After drying with MgSO4, the
combined extracts showed the presence of K[cis-
C2F5CF=CFBFn2OMe)3±n] [broadened resonances at ±83.2
23 F), ±117.9 22 F), ±135.6 21 F), ±151.0 and 153.6 2total 1 F)
and ±140.2, ±144.2 2B±F) ppm].
IR mª
2cm±1): 2961 s, 2932 s, 2875 s, 1707 s, 1626 w, 1468 m, 1434 m, 1374 w,
1315 m, 1292 m, 1266 s, 1207 s, 1156 vs, 1016 vs, 969 vs, 903 m, 880 s, 838 m,
751 m, 627 m, 581 m, 560 m, 491 w, 455 w.
Potassium trans-1,2-difluoro-2-phenylethen-1-yltrifluorobo-
rate (7). A solution of trans-1,2-difluoro-2-phenylethene
26.3 g, 45 mmol) in ether 2100 ml) was cooled to ±70 °C and
2.5 M BuLi in hexane 218 ml, 45 mmol) was added drop by
drop within 5 min. The reaction mixture was stirred for 1 h
at ±60 °C before B2OCH3)3 26.2 g, 59 mmol) was added.
After 15 min at ±60 °C the stirred solution was warmed to
room temperature within 1 h. The 19F NMR spectrum
showed the presence of trans-C6H5CF=CFB2OMe)2 [d2F):
±150.57 2F-1), ±164.38 2F-2) ppm; J, Hz: 2F-1,F-2) 109] and
Li[trans-C6H5CF=CFB2OMe)3] [d2F): ±160.16 2F-1), ±164.05
2F-2) ppm; J, Hz: 2F-1,F-2) 113]. The solution was concen-
trated under reduced pressure and poured into a solution of
K[HF2] 223 g, 396 mmol) in water 240 ml), MeOH 210 ml)
and 40% HF 220 ml). After stirring for 5 h the reaction mix-
ture was saturated with KF and extracted with MeCN
22 ´ 100 ml). The combined extracts were dried with K2CO3
and MgSO4 and evaporated under vacuum to yield po-
tassium trans-1,2-difluoro-2-phenylethen-1-yltrifluoroborate
25.2 g, 47%).
The extract was concentrated under reduced pressure, dis-
solved in MeOH 220 ml) before 40% HF 210 ml) was added.
The solution was stirred for 1 h, diluted with water 240 ml)
and neutralized with solid K2CO3. After evaporation to dry-
ness, the white solid was extracted with acetone 23 ´ 50 ml)
and the extracts were dried with MgSO4. The solvent was re-
moved, the residue was washed with anhydrous CH2Cl2
250 ml) and dried in vacuum to yield K[cis-C2F5CF=CFBF3]
29.5 g, 43% based on cis-C2F5CF=CFH).
C8H5BF5K 2246,03): calculated C 39.06, H 2.05, F 38.61;
found C 39.7, H 2.23, F 38.7%.
C4BF10K 2287,94): calculated C 16.69, F 65.98, found
C 16.7, F 66.0%.
IR mª
2cm±1): 3065 m, 3031 w, 1666 w, 1495 m, 1447 m, 1339 m, 1320 m,
1303 m, 1276 m, 1237 m, 1202 vs, 1188 m, 1114 m, 1091 s, 1068 vs, 1026 vs,
990 vs, 812 s, 762 s, 691 s, 633 m, 608 s, 592 m, 530 m.
IR mª
2cm±1): 1693 s, 1331 s, 1227 vs, 1167 m, 1135 s, 1058 s, 1006 vs, 959 s,
859 vs, 744 vs, 684 w, 643 s, 614 w, 543 m.
Potassium cis-perfluoroocten-1-yltrifluoroborate (4). A solu-
tion of 1 H,1 H-perfluorooctane 28.2 g, 20 mmol) in THF
2190 ml) was cooled to ±75 °C and 1.6 M BuLi in hexane
227 ml, 43 mmol) was added drop by drop within 15 min.
The reaction mixture was stirred for 1 h at this temperature
and then transferred into the pre-cooled 2±75 °C) and stirred
solution of B2OCH3)3 24.0 g, 38.4 mmol) in THF 240 ml).
The resulting suspension was stirred for an additional hour
at ±70 °C before it was warmed to room temperature within
3 h. The obtained solution was concentrated to ca. 80 ml vo-
lume under reduced pressure and poured into a solution of
K[HF2] 218.5 g, 237 mmol) in water 250 ml) and 40% HF
220 ml). After stirring overnight it was saturated with KF
and extracted with ether 23 ´ 50 ml). The combined extracts
were treated with K2CO3 and dried with MgSO4. After eva-
poration of the solvent the brownish viscous oil was washed
Potassium cis-, trans-chlorodifluoroethen-1-yltrifluoroborate
(2).
A solution of cis-, trans-1,2-dichlorodifluoroethene
29.2 g, 69 mmol) 2cis : trans = 47 : 53) in ether 2150 ml) was
cooled to ±90 °C and 1.7 M t-BuLi in pentane 241 ml,
69 mmol) was added drop by drop within 30 min. After stir-
ring for 30 min at £ ±83 °C, a solution of B2OCH3)3 27.2 g,
69 mmol) in ether 210 ml) was added within 5 min via a sep-
tum using a syringe. The reaction mixture was additionally
stirred for 40 min at ±85 °C and then warmed to room tem-
perature within 4 h. After concentration to ca. 70 ml volume
under reduced pressure the resulting viscous phase was
poured into a solution of K[HF2] 243 g, 551 mmol) in water
2130 ml) and MeOH 230 ml). The two-phase system was stir-
red for 2 h. The organic phase was separated, the aqueous
one was saturated with KF and extracted with acetone
2504
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505

2Fluoroorgano)fluoroboranes and -fluoroborates. 2
22 ´ 50 ml). The combined acetone extracts were dried with
MgSO4, before the solvent was removed.
References
[1] H.-J. Frohn, H. Franke, P. Fritzen, V. V. Bardin, J. Orga-
nomet. Chem. 2000, 598, 127.
[2] H.-J. Frohn, V. V. Bardin, Z. Anorg. Allg. Chem. 2001,
627, 15.
[3] Presented in parts: H.-J. Frohn and V. V. Bardin,
16th Intern. Symp. on Fluorine Chem., Durham (Great
Britain), 16±21 July 2000, 2 P±21.
[4] S. Martin, R. Sauvetre, J.-F. Normant, J. Organomet.
Chem. 1984, 264, 155.
[5] S. Martin, R. Sauvetre, J.-F. Normant, Tetrahedron Lett.
1982, 23, 4329.
[6] D. J. Burton, T. D. Spawn, P. L. Heinze, A. R. Bailey,
S. Shiya, J. Fluorine Chem. 1989, 44, 167.
[7] T. I. Filyakova, G. G. Belen'kii, E. P. Lur'e, A. I. Zape-
valov, Bull. Acad. Sci. USSR. Div. Chem. Sci. 1979, 28,
635; Izv. Akad. Nauk. SSSR. Ser. Khim. 1979, 681.
[8] T. I. Filyakova, A. I. Zapevalov, M. I. Kodess, M. A.
Kurykin, L. S. German, Izv. Akad. Nauk. Ser. Khim.
1994, 1614.
[9] K. K. Barnger, A. K. Brisdon, A. Gupta, Chem. Com-
mun. 1997, 139; J. Burdon, P. L. Coe, I. B. Haslock,
R. L. Powell, J. Fluorine Chem. 1997, 85, 151; J. M.
Bainbridge, S. J. Brown, P. N. Ewing, R. R. Gibson, J. C.
Percy, J. Chem. Soc., Perkin Trans. 1 1998, 2541.
[10] E. Vedejs, R. W. Chapman, S. C. Fields, M. R. Schrimpf,
J. Org. Chem. 1995, 60, 3020.
The residue was dissolved in MeOH 245 ml) and 40% HF
24 ml) was added. The solution was stirred for 2 h, diluted
with water 220 ml) and neutralized with solid K2CO3. After
evaporation to dryness, the white solid was extracted with
acetone 22 ´ 30 ml) and the extract was dried with MgSO4.
The solvent was removed and the solid dried in vacuum to
yield K[cis-, trans-ClCF=CFBF3] with an admixture of
K[F2C=CClBF3] 2ratio 44 : 46 : 9) 27.7 g, 54% based on
ClCF=CFCl).
C2BClF5K 2204,38): calculated C 11.75, Cl 17.35, F 46.48;
found C 11.1, Cl 16.9, F 47.0%.
IR mª
2cm±1): 1724 w, 1683 s, 1635 w, 1300 w, 1246 s, 1224 s, 1134 vs, 1080 s,
1028 vs, 969 vs, 880 s, 813 s, 655 m, 589 m, 534 w, 522 m.
The reaction of B(OCH3)3 with K[HF2]
K[HF2] 2234 mg, 3.0 mmol) was dissolved in water 20.93 ml)
and MeOH 20.30 ml) and B2OCH3)3 292 mg, 0.88 mmol) was
added under stirring. After 1 h the mother liquor of the sus-
pension was decanted and the precipitate was dissolved in
water. The 19F-NMR spectra of both solutions displayed
the resonance of the aqueous fluoride anion 2br, ±138 to
±145 ppm), of the [BF3OCH3]± anion 2±148.8 ppm; 1 : 1 : 1 : 1
1
quartet, J2FB) 15 Hz] [17], of [BF4]± 2small amounts) and a
[11] S. Darses, G. Michaud, J.-P. Genet, Eur. J. Org. Chem.
1999, 1875.
[12] N. A. Petatis, A. K. Yudin, I. A. Zavialov, G. K. S. Pra-
kash, G. A. Olah, Synlett 1997, 606.
weak unrecognized resonance at ±155 ppm 21 : 1 : 1 : 1 quar-
tet) which disappeared within 4 days. The final molar ratio
[BF3OCH3]± to [BF4]± was 96 : 4.
[13] D. J. Brauer, H. BuÈrger, Y. Chebude, G. Pawelke, Inorg.
Chem. 1999, 38, 3972.
[14] D. J. Brauer, G. Pawelke, J. Organomet. Chem. 2000,
604, 43.
[15] R. N. Haszeldine, J. Chem. Soc. 1952, 4259.
[16] A. Battais, B. Boutevin, P. Moreau, J. Fluorine Chem.
1978, 12, 481.
We gratefully acknowledge the financial support by
Deutsche Forschungsgemeinschaft, Russian Fonds of Basic
Research and Fonds der Chemischen Industry and the con-
tribution of chemicals by Clariant.
[17] V. N. Plakhotnik, V. V. Evsikov, E. V. Yanchenko, Koord.
Khim. 1976, 2, 855; N. S. Vasilyuk, B. N. Chernyshov,
Koord. Khim. 1981, 7, 78.
Z. Anorg. Allg. Chem. 2001, 627, 2499±2505
2505